Under the Full Moon
by Cela08
Summary: (Sun/Moon, TPB) With the help of Lunala, Moon and Hau decide to travel to another dimension for fun. But things go awry when the two get separated from their Pokemon on the way! Meanwhile, Tigerclaw plots to overthrow his leader, but the strange arrivals may throw a wrench in his plans. ...and hopefully, nothing followed Moon and Hau through the wormhole they came in on.
1. Prologue

**author's note: hey WOW it's been a gazillion years since i've been on this account! holy heck! anyway. here's a freaking sun/moon warrior cats crossover fic.**

 **on the sun/moon side of things, it's placed after the main plot. so there will DEFINITELY be spoilers for the entirety of pokemon moon. on the warriors side of things it's set during forest of secrets in the first series, shortly before the gathering. there'll be spoilers there, too, but the plot will end up taking a far different course than it does in canon.**

 **by the way, only a couple ocs are planned to appear, they're just the pokemon i had in my team in pokemon moon. this may change when i'm later in the story, but i at least don't plan to write in any more ocs.**

Wind whipped around the two children's ankles, a slight chill from the mountaintop air brushing against them. Perhaps t-shirts and shorts were a tad light for wearing atop the Altar of the Moone, but there could be worse. It was better than Mount Lanakila, after all.

A wide grin full of childish excitement stretched across the young champion's face. "I still can't believe you agreed to do this."

"How come? This sounds great!" the grandson of Melemele's kahuna laughed. "I can't be left out of all the fun adventures!"

The champion, Moon, guessed that he was referring to the Ultra Space incident - she'd hardly call it a fun adventure, but she still understood why he would've felt left out considering he had just been off doing island trials while she and Lillie had visited a whole other dimension.

"Alrighty, let's rundown the plan one more time: we have Nebby make an Ultra Wormhole to a surprise dimension - emphasis on surprise, I _really_ don't know what else's out there we can visit other than Ultra Space - explore a bit and have a good time, and then have Nebby take us right back here." She paused a bit before adding, "Or if something goes wrong, Nebby takes us home early. You _sure_ you're up for this, Hau?"

He seemed to contemplate it a little longer than his unhesitant response before, but he kept his enthusiasm. "Yeah, of course!"

In reply, Moon tossed a Luxury Ball into the air, it opening to release a shimmering beast much like a bat - the legendary Lunala, embodiment of the night... or as Moon and Hau knew them, Nebby.

Nebby let out a powerful and triumphant-sounding cry which nearly shook the altar, the air crackling with powerful energy. Both they and Moon had been wanting to do this for a while. Though despite the commanding presence that a being of their caliber should posess, they lowered their head so Moon could pet it, looking joyful. Truthfully, having still been a Cosmog such a short time ago, Nebby was as much of a child as the two standing before them were.

"C'mon Hau, what are you waiting for?" Moon's eyes shimmered with excitement which neither Hau nor Nebby had seen since she became the champion. "Let's go explore someplace nobody has ever seen or maybe even heard of!"

He nodded quickly with a big smile, grabbing her hand as Nebby swooped down and picked the two up in great, star-flecked wings. The Lunala shot a beam into the air which pierced the void between dimensions, and swiftly rushed through it.

Despite shielding his face from the wind, Hau still managed to catch a glimpse of Ultra Space in between their dimension and the next. It was bizarre yet pretty in an odd way, and only left him more curious what the place they were going would be like.

...Truthfully, neither Moon nor Nebby had any idea. Nebby found their feeling of control over their power exhilarating, and almost had to stop themself from showing off and twirling about through several different realities. While Moon had been in this idea for the adventure, Nebby had really just wanted a chance to stretch their wings.

Unfortunately, irresponsible children with no plan were bound to get themselves in trouble. Nebby had no practice with this sort of thing - when would they have had the chance? - and as they flew through the wormhole, things went out of control. They had really hoped they had a bit more stamina, and perhaps been better at handling crash-landings, but... The last thing they thought as they lost consciousness in some sort of oak forest was that they desperately hoped Moon and Hau were unharmed.

When Nebby came to, they realized in horror there was no sign of either anywhere. Taking in their surroundings, they spotted the bags of the two on the ground, and among the smashed trees left by the crash there lay at least one feline Pokemon of a kind which Nebby had never seen before. They called desperately to the sky, the lingering scent of the Ultra Wormhole permeating the air and making it impossible to find them by wormhole energy alone. When no reply came back to them, Nebby carefully picked up the backpack and bag of the two children, and took off into the night sky in search of them.

Where the Ultra Wormhole had formed and closed, invisible cracks split the veil between worlds.


	2. Chapter 1

Bluestar was swiftly and unpleasantly jolted from her sleep by a strange and otherwordly screech piercing the night sky. It didn't quite sound like something any sort of creature she'd ever heard of could make. She would have dismissed it as a strange dream, were it not for her Clanmates coming out of their dens, clearly jolted from sleep by the same sound. Confused murmurs and fearful whispers were traded around the clearing.

"Do... do you think we should investigate?" Fireheart asked, approaching Bluestar.

"I bet it's just something weird a twoleg caused." Speckletail said idly, her bored tone betrayed by her fear-scent. "Who knows with them, after all."

"Then I suppose Fireheart should go take care of it - after all, he's the kittypet!" Darkstripe loudly said, making sure Fireheart could hear it. Longtail purred in amusement, but Tigerclaw flicked his tail to quiet the two.

"Bluestar, I recommend we send a small patrol to investigate. Until we know if it's a potential threat to the Clan, we need to take this seriously." Despite use of the word "recommend", there was a certain way to how he spoke which made it clear that was the only option in his eyes.

Nodding, Bluestar climbed to the top of the Highrock, calling down to the rest of the Clan. "All cats old enough to catch their own prey, gather under the Highrock for a Clan meeting!"

The few cats who had slept through the initial cry were roused from sleep, blearily stepping outside among the other tired cats. Mumbles and complaints spread around the clearing, but stopped once Bluestar spoke up again, her eyes shining with worry in the moonlight.

"Most of you have already heard the unusual sound from somewhere within our territories. As we don't yet know where or not it's a potential danger to the Clan, we're sending out a small patrol to find its source and report back." She stopped for a moment, looking over the rest of her Clanmates. "Dustpelt, Graystripe, and Tigerclaw, you will all be going to investigate. Everyone else, stay on guard in camp, just in case."

Dustpelt groaned something about wanting to go back to sleep, while Graystripe had to stop himself from shrinking back as Tigerclaw glared daggers into him, leaving him wondering just how much the intimidating deputy knew about his relationship with Silverstream.

There was a tense and uncomfortable silence most of the way there - Dustpelt considered breaking it, but thought better of it. But eventually, a mixture of overpowering scents washed over them: twoleg, loner or kittypet, bat?, and something strange and indescribable that seemed to make the very air harder to breathe. It sent chills down Graystripe's spine.

"Should've known twolegs would have to do with this," Tigerclaw hissed, heading towards the source of the scent. Despite his voice being cold, Graystripe could tell from the way his fur bristled that even Tigerclaw could tell just how _wrong_ the scent was.

Dustpelt stuck close to Tigerclaw, either not noticing the fact that he was equally scared or willingly ignoring it. "Yeah, twolegs are always causing trouble, huh? Like... like... whatever this is."

They all nearly gasped at the sight of the fallen trees, some reduced to splinters as if something very large and _fast_ smashed into them. It was visible that even Tigerclaw had no idea what to make of it, but when his eyes fell on the two injured kittypets lying in the mess, Graystripe could see his demeanor harden.

"Kittypets!" Dustpelt spat. "Surely they didn't do all this, right? We need to chase them off!" He lashed his tail, already prepared to fight.

Graystripe was taking great pity on the two. "They're in terrible shape and already unconscious. You sure they aren't already dying?" He cleared his throat, trying to think of a way to stop them from picking a fight against someone who was in no condition to fight back. They looked to be hardly even apprentice-aged, for StarClan's sake! "Bluestar did only say we were supposed to report back, and... if they die, we could lose our only chance to find out what happened here."

Tigerclaw considered it for a moment, his amber eyes flashing with annoyance towards Graystripe. "Fine. We'll take them back to camp and question them once they wake up, but then they're leaving. By force, if necessary."

It was better than nothing, at least. The two kittypets could end up being more dangerous than they looked, but somehow Graystripe doubted it. He padded over to one of the two young cats, a black and white she with a strange stone ring around one of her front ankles, and alarmingly a piece of bark from the smashed trees lodged in her side and trickling blood. He picked her up in his scruff as gently as he could, and out of the corner of his eye he saw Dustpelt hesitantly do the same for a small dark brown tabby with a similar stone ring. Tigerclaw stood in front and lead the way back to camp, clearly not interested in carrying either one of the kittypets.

"We should probably take them to Yellowfang first thing, even if she's grumpy about it," Graystripe mewed through a mouthful of fur, getting a nod from Dustpelt in reply.

Back in camp, the guard duty was both boring and nerve wracking, a few apprentices even jumping at the smallest noise. However, most cats were visibly relieved when they spotted the returning patrol in the distance. Relief turned to slight confusion upon noticing the unconscious kittypets they held, and for many confusion turned to concern upon seeing the condition the kittypets were in.

"We need to see Yellowfang and Cinderpaw right away!" Graystripe said through muffled fur as Tigerclaw headed over to Bluestar to give a report.  
The two cats were taken and placed in the medicine cat den, and almost hesitantly Dustpelt was the one to nudge Yellowfang awake, not particularly wanting a tongue-lashing from her.

"What is it...? Thorns in your nest?" she meowed, groggy and half-asleep. "Don't you know never to wake up a grumpy old badger like me at this-" She turned around and saw the two young and wounded cats, her yellow eyes widening in sympathy. "Where'd you end up finding _these_ ratty kits, then?" Despite her remark, she was already hurrying to tend to them, removing the splinters and pressing cobwebs onto the wounds and scratches.

Graystripe watched with concern while also trying to figure out where they came from, but Dustpelt's voice cut through his thoughts. "There was a strange noise in the forest, and we found them in the place we investigated."

"What kind of place in the forest would give them splinters like this? It looks like the trees exploded overtop of them!" Yellowfang asked, more snappily than necessary.

"Well, uh..." Graystripe's tail twitched uncomfortably. "From how the part of the forest where we found them looked, that may as well have been what happened."  
Yellowfang wasn't exactly sure how to reply to that. "Well... these two will be fine, as long as their injuries don't get infected. Now, get out of my den. I was having a great sleep before you and your mystery kittypets came in."

"Alright. Thanks, Yellowfang," Graystripe said quickly, heading to the warriors den to get some well-deserved rest.

"Watch out for the exploding trees," Yellowfang called after him, though he barely paid attention as he drifted off into sleep.


	3. Chapter 2

Hau yawned and stretched, the morning sunlight nearly blinding him. What happened last night? He was riding on Nebby with Moon last night, and then...? Shifting a little bit, he felt pain all over his body. Even despite that, his body didn't quite move the way he wanted it to, like his joints were suddenly shaped all wrong.

His eyes adjusted to the light, though, and he drew in a gasp upon seeing that where there should have been hands, there were instead _paws._ Hold on... was he a Pokemon?! Strange... but at the same time, he thought it was kind of cool!

He took in his surroundings - some sort of grassy cave, with a pool in one corner. There were leaves of all sorts of different plants stuffed into cracks in the rock wall. By his side, there lay another Pokemon that he guessed was the same kind as him. The Pokemon was a feline species he had never seen before, with short black and white fur. Worryingly, they had multiple wounds covered with blood-soaked webbing. He sure hoped they were alright...

"Oh, you're finally awake!" a chipper voice called through Hau's thoughts. "You two looked pretty bad when we found you, but it looks like the wounds are healing nicely."

He turned to face the source of the voice and was greeted with a dark-furred Pokemon of the same kind. Her blue eyes shimmered with relief at seeing that at least one of the two was alright.

"Hey, where am I?" he asked as casually as he could in this situation, not entirely surprised to hear a Pokemon talk. After all, it only made sense if he was now the same species as her.

"Oh, you're in the ThunderClan medicine den. We found you unconscious in a destroyed part of the forest with that other cat there." She gestured with her tail tip towards the sleeping Pokemon - were they really just called cats? maybe they didn't have the word "Pokemon" in this world. "Hold on, I'm going to call the medicine cat in. Yellowfang, one of them's awake! And they both look like they're healing well!" she called through the entryway to the cave.

A harsher, more aged voice called back. "They'd better be, after all the splinters we had to get rid of!"

"Splinters?" Hau asked, noticing for the first time that he was also covered in bloodied webbing.

The cat in the entryway tilted her head to the side slightly. "So you don't know what happened, either?" She sighed. "Where we found you, it was like a powerful storm hit the trees and shredded them apart. There were splinters everywhere, but you and your friend there had it especially bad. If our patrol hadn't found you, you might've just bled out there."

Through the entrance came another cat, a ragged-looked one with a black pelt. She definitely looked as cranky as she sounded! Her intense orange eyes looked him and the cat by his side over.

"I'm Hau," Unprompted, he introduced himself to the strangers. "What're your names?"

The one with the blue eyes looked a little startled at his abrupt introduction. "Oh! I'm Cinderpaw, and this is my mentor, Yellowfang. I'm training to become a medicine cat like her."

The one with the orange eyes - Yellowfang - twitched her tail. "Hau's a very strange name." She headed over to the still-unconscious cat, examining the wounds. She continued to speak while doing so. "What brought you to ThunderClan territory? I thought kittypets told their kits horror stories about us Clan cats eating them and sharpening their claws on their bones." She had a joking and sarcastic tone to her voice as she spoke.

Hau didn't really understand terms like "kittypet" and "ThunderClan", but decided to play along as if he did. They'd probably think he was nuts if he said he was a human from another dimension, after all! "Well... as long as you don't really do that, I think you're fine!" He contemplated for a bit what to say next without possibly making them mad. "I didn't know this was anybody's territory. Sorry about that!" He grinned in a silly way and shrugged as best he could on four legs.

"You're an... interesting one, huh?" Cinderpaw said, looking a bit baffled at both how laidback he was and the weird gesture he (attempted to) make.

Suddenly, a thought struck Hau. If he was a Pokemon now, then that meant Moon probably was as well, and how could he have not even realized, it was so obvious- He quickly turned to the sleeping cat by his side.

"She's fine and looks to be doing better," Yellowfang assured, easily guessing what he was about to ask.

Unhesitatingly, he nudged Moon awake, breathing a sigh of relief when she opened her eyes.

She blinked a couple times before really registering the sight of the Pokemon frighteningly close to her face and scrambled backwards as best she could, her body strangely uncooperative. "W-whoa!" She reached for where her bag would be to grab a Pokeball and send out one of her Pokemon to defend her, but swiftly escalating panic blossomed in her stomach as she realized her bag wasn't there and hold on those weren't hands those were _paws_ and she was _some kind of Pokemon_ and her escape was totally blocked off she might have to _fight her way out-_

"Hold on, Moon! It's me, Hau! Calm down!" Hau was startled by her panic, seeing her hiss and her fur totally fluff up.

Recognition flared in her eyes and she calmed down a bit, still visibly confused and scared. "Hau? Where are we? What even happened?" She turned her dark grey-blue eyes over at the two other cats in the room. "And who are they?"

"We are the ones trying not to get our pelts ripped off by the kit we just rescued." Yellowfang remarked, tail lashing in annoyance at Moon's way of "thanking" them.

Hau stopped to see if he could remember any of what happened after they went through the Ultra Wormhole. "Something happened when we were travelling with Nebby, but I can't actually remember... But we're in some sort of 'ThunderClan' place, and those two over there" - he pointed towards Yellowfang and Cinderpaw with his paw - "healed us."

"I didn't know a single cat could get as many splinters as you two each did." Cinderpaw put in. "One of our patrols found you and felt sorry for you, because you were both in terrible shape."

"I'd rather you not speak for me, Cinderpaw." A powerful and somewhat disdainful voice spoke from just outside. The owner of the voice, a large and frightening brown striped cat, shouldered his way in. His amber eyes burned with disgust towards Hau and Moon. "I would have far rather chased these kittypets off our territory than welcome them right into the heart of it."

"Tigerclaw, we don't even know if they are kittypets." Cinderpaw defended them. "Either way, we couldn't have chased off two dying kits. Not only is it against the warrior code to neglect a kit in need, but it's also just plain immoral."

He narrowed his eyes, feeling disrespected. "We only brought them in for an explanation as to why a chunk of the forest was reduced to _twigs._ It sounds to me, though, that the only ones that have been answering any questions are you two."

"Cinderpaw, you shouldn't talk that way to your deputy." Yellowfang warned, though there was something in the way she said that which gave Moon the feeling she would've also said something along the lines of "no matter how unpleasant he is" if Tigerclaw wasn't listening.

Clearly, Tigerclaw didn't pick up on the unspoken insult, as he simply nodded in agreement. "How long do you think it'll be before they can leave?"

"They can barely even stand on their paws. It may be several days until they have regained their strength." Yellowfang explained, flicking her tail dismissively. "Be patient, it's not like they've came here to join the Clan."

"I'm sure if they did, that kittypet-loving Bluestar would've let them join without hesitation," Tigerclaw muttered under his breath while leaving, though the two humans-turned-cats overheard.

"Man, he must be fun to answer to, huh?" Hau said jokingly.

"Yes, he's a very strict deputy." Yellowfang admitted. "I'm not looking forward to the day he becomes leader - it certainly won't help his ego."

Moon's ear twitched slightly as she had other things on her mind. "Uh, can I talk to Hau alone for a minute, please?" As she said this, Hau looked over to her, confused.

Cinderpaw looked to Yellowfang for an answer, and got a nod in reply. "Alright, but not too long." The two walked out of the den slowly, Moon waiting until they were both out of sight.

"What's up?" Hau asked, one of his ears tilted to the side.

Moon looked stressed. "Hau. Our bags. Where are they?" Her tail was twitching ever-so-slightly.

"Uh, I'm not really sure." He awkwardly shrugged. "Nobody said anything to me about any sort of bags either. Why?"

"Our Pokeballs are in there. And if we don't have our Pokeballs, we don't have our Pokemon." Her claws dug into the ground. "And if we don't have our Pokemon, not only do we have no way of defending ourselves unless we learn to fight, but _without Nebby we have no way of getting back to our world!"_ Her eyes were as wide as plates, and her tail was fluffed up to twice its size. "We don't even know if they came with us or not, and I'm not sure which option's worse!"

The same panic which had tightly gripped Moon found its place on Hau. "Wait, what?! So we're in serious trouble this time..." He tried to get to his feet and walk despite the pain, testing his legs. However, his mind couldn't make heads or tails of walking with a cat's body, and he collapsed. "We better learn how to walk first before we go searching for anything!"

Moon took a deep breath, finally letting her fur lie flat. "I guess you're right."

Just outside the den, the ears of of a certain power-hungry deputy were pricked to eavesdrop.


End file.
